Permissions

Hello all,

I've been trying to figure a few things lately but I could not so I'm
asking on the list. I need to programmatically (through JDBC):

1. Figure out if the currently logged in user can create a schema
2. Figure out if a role has USAGE privileges on a schema
3. Figure out if a role has CREATE privileges on a schema
4. Figure out if a user can create a table in a schema

I've been reading the online docs but I could nowhere see any examples
of finding out that information through the information_schema schema. I
was advised not to poke around with the pg_* schemas since they can
change frequently. What I need to do is basically ensure that a user can
create a schema, then create some tables in that schema and ensure that
other users can access these later. Is is possible that a user can be
given for example SELECT privileges to a table in a schema but he/she
would not be able to access the table because they don't have USAGE
privileges on the schema which the table belongs to? I have found out
that I can retrieve all the necessary permissions for tables from the
information_schema.table_privileges table with no problems but I'm
puzzled about database & schema privileges.

Kind regards,
gamehack